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Trailer lights can pull more current than a vehicle’s tail light circuits are designed to handle. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector uses a powered converter module that draws power directly from the battery. That protects the vehicle wiring from overload and keeps the trailer lights operating as they should, even when running multiple bulbs or LED lights.
A lot of lighting problems come down to not having a clean power source. This harness includes a dedicated 12-volt line that feeds the converter straight from the battery instead of pulling power through the vehicle’s tail light circuits. It gives consistent output for running lights, turn signals, and brake lights, so everything on the trailer stays bright and synced.
Wiring up a trailer connection can look intimidating, but this setup keeps it simple. The T-Connector plugs inline with the vehicle’s factory tail light connectors, so there’s no cutting or splicing involved. Once connected, you just run the included power wire to the battery and mount the converter box in the open cavity below the driver’s side tail light.
The included 4-pole flat connector gives you what most small and mid-size trailers use—running lights, turn signals, and brake lights. It’s the standard hookup for utility trailers, campers, or boat haulers, and it’s ready to plug into your trailer wiring right out of the box.
Earlier versions of this harness used an older converter that could short under heavy load. The updated design in this model uses a newer high-amperage converter box that holds up better over time and handles more trailer lights without issues. It’s made to deliver stable power every time you hook up.
Customer Satisfaction Score:
97% were satisfied with this product
3% of customers were not satisfied
Ratings & Reviews
Fit very nicely and easy. It was a pain to wire the module directly to the battery but worth it
Easy enough to install that I could do it in my driveway in two hours.
Box was half torn apart with no packaging in sight. Disgraceful. The wiring package was clear taped together and I hope it will work with my vehicle for plug and play as its years stop at 2017 and mine is a 2019. The year manufacturer date on the product is 5/19/2022 as there is dust all over it. Just not satisfied but I guess that what it is.
I just got it installed today and it looks great. Looking forward to towing my trailor soon.
I had this professionally installed for occasional utility trailer use. Works as expected .
This fit my vehicle perfectly. The install was fairly easy and the instructions were clear.
Great product but a pain to fish wires through. Easy to figure out what goes where.
SUPER easy to install. Pay attention and it'll be a cake walk. I say pay attention because I installed it backwards (the left and right turn signals were opposite the car). Other than that, clear directions and all supplies needed unless you modify it like I did in a few spots.
I needed a replacement controller and harness for my 2011 Ford Flex. etrailers had exactly what I needed and I got it unbelievably fast! Great job all around!
Video of installation was very good. It took me slightly longer than suggested but I did the installation y myself.
I had it installed along with a hitch I bought earlier. Went beautifully.
Purchasing process from etrailer was easy, shipping was very prompt, wiring installation was not difficult. Only disappointment was the lack of a solid support for final connector.
The only thing that was unclear during the installation was which side the "Y" connectors needed to go. Looking at the diagram, in relation to the vehicle, I made a guess which turned out to be correct. It would have been nice to have them labeled as "driver side" and "passenger side", or something like that to remove the guess work.
Fast shipping, clear instructions. Tough install on Ford Flex only because few components underneath to zip tie power lead to. I used rear climate control tubing. No way to know yet whether heat cycles will affect wiring. Once installed, has worked perfectly so far.
Works excellent but it didn't come with any installation instructions. I had a bear of a time routing the wiring. Just take your time, plug into the taillights first, then mount the converter box. The rest will fall into place after that.
It took about an hour and a half to install the factory hitch and this t connector kit. Definitely worth the extra work to run the wire to the battery,better safe than sorry. Good quality kit and shipped fast!!!!
The Curt wiring harness is exactly as advertised and undoubted a good product seeing that it is from Curt Manufacturing. What impresses me the most with this purchase was the communication and quick shipment. I ordered on a Sunday afternoon, used economy shipping and received on Thursday morning. In between getting shipping updates and notification of shipment. Can't do better than that! Therefore I will use etrailer.com for future needs and definitely recommend to others. Thank you etrailer!
Very complete kit. Fairly easy to route. would be great if Curt included the upgraded heat shrink connectors as shown in etrailer's install video. Luckily I had some extra heat shrink on hand. I also used some split loom to further protect the wiring, especially in areas where it routed around a sharp corner and of course larger zip ties due to the increased size of the split loom.
The service was great. They processed and shipped my order the same day I contacted them. And, as always (I've ordered multiple times from trailer), the products are the best.
I would not buy this wiring harness again. It is not worth the additional work to run a dedicated power wire. Go with the plug and play model.
Jenny N.
2/10/2022
The powered tail light converter connects directly to the battery to avoid overloading the vehicles electrical system. We do have a great FAQ that provides ideas on ways to route the power wire. There is non powered harness for the 2019 Ford Flex. It is part # 118472.
We purchased this product for the second time after the first one shorted out due to moisture getting in my vehicle tail lights. Fortunately, our son-in-law is an automobile technician and is gracious enough to install the wiring kit as I'm sure neither my husband nor I would be able to manage it. Once installed, it has worked reliably with our 8' utility trailer.
Barbara
10/21/2020
The Curt wiring harness is still functioning a year after purchase and months of sitting idle.
Bolting on the hitch took about 15min and was easy to do with the bolts provided and after watching the quick video on installing it.
Wiring it up on the other hand took a while. The instructions that came with the electrical was easy to follow and super helpful...finding a path for the wires underneath the car from the battery back to the hitch is what took the longest.
Bolting on the hitch took about 15min and was easy to do with the bolts provided and after watching the quick video on installing it.
Wiring it up on the other hand took a while. The instructions that came with the electrical was easy to follow and super helpful...finding a path for the wires underneath the car from the battery back to the hitch is what took the longest.
delivered fast on time well packaged in crumbled up sheet. excellent tracking info bettercthan others tracker.
Michael
5/25/2026
Work good so far used it twice.
Lazer S.
5/25/2026
After UHaul gave me a price figure on installation of the trailer hitch and wiring kit I purchased from etrailer.com that was 25% MORE than the hitch and wiring kit themselves, I made it a point to "man up" and install the products myself.
Not only was the installation process straight forward and relatively simple, the installation works perfectly and has made me a "proud poppa" as I'm now able to haul what I need, when I need it hauled.
etrailer.com's team was 100% professional and helpful throughout my purchase and installation process. I recommend the company and their products without reservation.
James D.
5/27/2026
Love to hear this Kerry! Smooth and easy install is always a win. We appreciate your kind words and thanks for choosing etrailer!
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Jenny N.
3/23/2023
It sounds like the box and wiring had a tough journey. I checked and this harness is a fit through to 2019 Ford Flex. Customer Service will be in touch with you in case there is any damage or missing parts.